Fluid catalytic cracking apparatus

Abstract

Apparatus for catalytic cracking of a selected portion of a hydrocarbon feedstock comprising a riser reactor and a catalyst regenerator, a regenerated catalyst cooler, and an absorber. Regenerated catalyst from the catalyst regenerator is conducted through the catalyst cooler into the absorber where it adsorbs hydrocarbon cracking feedstock and then returned to the riser reactor. A duct carries part of the hot regenerated catalyst from the catalyst regenerator directly to the riser reactor to supply heat for cracking the hydrocarbon feedstock.

We claim: 
     
       1. In a fluidized catalytic cracking apparatus which comprises a riser reactor, a catalyst regenerator, means for transferring regenerated catalyst from the catalyst regenerator directly into the riser reactor, and means for transferring spent catalyst from the riser reactor into the catalyst regenerator, the improvement which comprises an adsorber, a catalyst cooler, means for transferring regenerated catalyst from said catalyst regenerator into said catalyst cooler, means for transferring catalyst from said catalyst cooler into said adsorber, means for introducing vaporized hydrocarbon cracking feedstock into said adsorber, means for discharging unadsorbed hydrocarbons from said adsorber, and means for transferring catalyst containing adsorbed hydrocarbons from said adsorber to said riser reactor as a source of feedstock and catalyst for said catalytic cracking reactor. 
     
     
       2. In a fluidized catalytic cracking apparatus which comprises a riser reactor, a catalyst regenerator, means for transferring regenerated catalyst from said catalyst regenerator directly into said riser reactor, and means for transferring spent catalyst from said riser reactor into said catalyst regenerator, the improvement which comprises an adsorber, a catalyst cooler, means for transferring regenerated catalyst from said catalyst regenerator into said catalyst cooler, means for transferring catalyst from said catalyst cooler into said absorber, means for introducing vaporized hydrocarbon cracking feedstock into said adsorber, means for discharging unadsorbed hydrocarbons from said adsorber, and means for transferring catalyst containing adsorbed hydrocarbons from said adsorber to said riser reactor wherein said cooling means comprises a heat exchange element constructed so as to effect indirect heat exchange between hot regenerated catalyst from said regenerator and a liquid hydrocarbon cracking feedstock, and a vapor-liquid separator in flow communication with said heat exchange element so as to receive the liquid hydrocarbon cracking feedstock and including means for transferring separated hydrocarbon vapors from said separator to said absorber. 
     
     
       3. Apparatus according to claim 2 wherein said catalyst cooling means comprises a vertical cylindrical heat exchanger vessel containing said heat exchange element and provided with means for introducing a fluidizing gas into a lower portion of said heat exchanger vessel and for discharging the fluidizing gas from an upper portion of said heat exchange vessel.